1. Field of the Invention
The present invention relates to a job execution control method and apparatus for a computer system which is capable of executing at least one job, and more particularly to a job execution prediction control method and apparatus for executing jobs in accordance with a job execution schedule set prior to the execution of the jobs, as well as a job execution situation display method.
2. Description of the Related Art
A job execution control method for a computer system in general tends to simultaneously execute a plurality of jobs with the development of a multi-programming control function of the operating system. However, if a large amount of jobs are to be executed at a time, the jobs may contend for limited resources of a computer system, thus incurring fear of degrading the performance of the computer system. As a method for solving this problem, a method has been devised, where jobs having similar processing characteristics are collected into a group (classification of jobs), and the execution of the jobs is controlled in the unit of the job class. According to this method, the number of simultaneously operated jobs can be limited to the number of classes. A job execution control using this method is described in "VOS3 Center Operation -Series JSS3- Hitachi Works HITAC Manual, 8091-3-001", pp 18-24. However, this method has a problem that, by setting classification of jobs and limiting the number of simultaneously executed jobs, a queue of execution waiting jobs is formed in each job class if jobs in the same class increases. This execution waiting queue is very troublesome for a job feeder. More specifically, if an execution waiting job queue exists at the time a job feeder has fed a Job, the feeder cannot know when the job is executed and when it will be ended. Among jobs, there are many which must be each started the execution at a predetermined time.
To solve this problem, a method has been devised for executing jobs according to a job schedule set prior to the execution of the jobs. In this method, an execution start time is previously set for each job, and a job schedule management program orderly executes the jobs at their set execution start times. This method is described in "Integrated Operation Management System HOPPS3 Summary, Hitachi Software Engineering HITAC Manual", pp 35-36. This method enables a job to start at a set time.
On the other hand, U.S. Pat. No. 4,495,562 shows a method which uses a processing history of a computer system to calculate an execution service rate (ESR), which is a performance index indicative of the processing speed of a job, and utilizes the ESR to determine to which computer the job is assigned in accordance with workloads of computers, thereby improving the throughput of the computer system. Incidentally, the definition of ESR is described in "One System for Performance Management in a Computer System and Experiment Using the Same", Transactions of the Institute of Information Processing, Vol. 23, No. 6, Nov. 1982, pp 591-597.